Device for mixing and dispensing foam forming solutions



June 23, 1959 P. K. WELFORD 1,

DEVICE FOR MIXING AND DISPENSING FOAM FORMING SOLUTIOILIS Filed March 11, 195? 16 F1. g}. .L 1a

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United States Patent DEVICE FOR MIXING AND D I SPENSING FOAM FORMING SOLUTIONS Phillip Klaus Welford, Bedford, Nova Scotia, Canada Application March 11, 1957, Serial No. 645,279

4 Claims. (Cl. 252.-359) The present invention relates to a device for mixing and dispensing foam-forming solutions.

There are devices at present inuse for mixing and dispensing solutions which provide for the controlled injection of foam-forming liquid into a stream of water. However, in these prior devices the resultant mixture is dispensed only in the form of a liquid spray or stream which must subsequently be worked into foam or suds. Prior devices are also subject to the disadvantage that the apparatus controlling the injection of foam-forming liquid into the stream of water is inaccessible and incapable of fine adjustment by an operator.

An object of the invention is therefore to provide apparatus of the type described which is capable of instant control.

More specifically there is provided according to the invention, a restriction in the outlet passage of a stream of water which creates an area of partial vacuum in the passage downstream from the restriction, a passage leading from a reservoir for foam-forming liquid into the area of partial vacuum allowing the foam-forming liquid to be drawn into the stream by the partial vacuum, and means for bringing the area back to atmospheric pressure thereby creating in the passage a clear stream of water or a foam-forming mixture as desired.

It is a further object of the invention to provide a device as described above in which the foam-forming liquid is admitted to the stream of air for the development of foam.

These and other objects of the invention will appear from the following description with respect to the drawings illustrating one embodiment of the invention in which:

Figure 1 is an elevation, partly in cross-section, of the device; and

Figure 2 is a fragmentary enlargement of the air valve means, tube and chamber structure shown in Figure 1.

In the embodiment shown in the drawings, the device comprises a body portion having a main longitudinal bore 11 extending throughout its length from an upstream inlet end 12 to a downstream outlet end 13. The body portion 10 is internally threaded at inlet end 12 to receive a feed pipe 14 and is externally threaded at outlet end 13 to receive a spray head 15.

A restriction is formed in the bore by convergent nozzle 16 positioned, for instance press fitted, concentrically within bore 11 downstream from inlet end 12 thus forming a restriction in bore 11. Nozzle 16 converges downstream within bore 11, having its orifice 17 remote from inlet end 12 of the bore. The outer periphery 18 of nozzle 16 adjacent orifice 17 forms an annular chamber 19 with bore 11.

An annular shoulder 20 in bore 11 adjacent and downstream from orifice 17 of nozzle 16 provides a further defining wall for chamber 19. From shoulder 20, bore 11 diverges downstream towards outlet end 13 of body portion 10 in order to decrease the velocity of flow in the hoe bore and prevent pressure building up at the outlet. The diameter of the bore at shoulder 20 is greater thanthe diameter of orifice 17 of nozzle 16 in order to accommodate the expanding jet issuing from the orifice.

A passage in the form of a siphon tube 21 opens, through body portion 10, into chamber 19 opposite the outer periphery 18 of nozzle 16. Tube 21 extends down wardly from body portion 10 into a reservoir 22, terminating close to but spaced from the bottom 22a of the reservoir. An air flow regulating valve 23 comprising a port 24 and a valve pad 25 also opens into chamber 19 through body portion 10 adjacent shoulder 20.

Reservoir 22 is detachably'secured beneath body portion 10 by means of struts 26 and 27 which carry a cap 28 at their ends remote from the body portion. The flange 28a of cap 28 is internally threaded to receive reservoir 22. As an alternative,'flange 28a might be internally ridged and reservoir 22 pressfitted into position.

Valve pad 25 is secured at one end of a lever arm 29 which is pivotally mounted, intermediate its ends, on a pin 30. Pin 30 is supported on an ear 31 attached to rear strut 27. A chain 32 or other suitable pulling means is attached to the end of lever arm 29 remote from valve pad 25 and hangs clear of reservoir 22. Valve pad 25 is held in an inoperative position away from port 24 by a coil spring 33 which is anchored at one end to lever arm 29 and at the other end to cap 28. A breather port 34, which is provided in cap 28 for reservoir 22, may be conveniently used to anchor spring 33 as shown in Figure 2. An opening 35 in cap 28 allows siphon tube 21 to pass into reservoir 22.

In the preferred form of the invention (see Figure 2), the valve pad 25 does not fit snugly against port 24 but is set on the lever arm 29 at an angle to the body portion 10 in order that a slight leakage of air may occur.

In the operation of the device, a stream of water enters bore 11 from feed pipe 14 and passes downstream through nozzle 16 wherein it is forced to converge. This causes an increase in the velocity of the water. Continuing its flow, the stream of water issues as a jet from olifice 17, the velocity of the stream causing it to overshoot chamber 19 and wipe bore 11 downstream from shoulder 20.

The stream issuing as a jet from orifice 17 of nozzle 16 is below atmospheric pressure due to its increased velocity and consequently creates an area of partial vacuum in chamber 19. When valve pad 25 is in inoperative position and valve 23 is open, the pressure differential between the vacuum and the atmosphere is immediately and continuously corrected. When, however, the chain 32 is pulled and valve pad 25 is brought into operative position to substantially close oif port 24, the partial vacuum in chamber 19 causes foam-forming liquid to be drawn from reservoir 22 into the chamber.

The foam-forming liquid drawn up from reservoir 22 into chamber 16 impinges on the outer periphery 18 of nozzle 16 and is dispersed towards shoulder 20. The liquid then strikes shoulder 20, is further dispersed and entrained in the jet of water crossing the mouth of the chamber 19 as it issues from orifice 17 of nozzle 16. The small amount of air leaking through valve 23 when valve pad 25 is in operative position is also entrained in the jet of water issuing from nozzle 16. This admixture of air with the liquid from the reservoir 22 and the water from nozzle 16 creates a solution which is worked into a rich foam when it strikes the spray head 15.

To obtain a spray of pure water rather than foam issuing from spray head 15, the operator merely releases chain 32 which, by means of spring 33, returns the valve pad 25 to its inoperative position and brings the area of partial vacuum in chamber 19 back to atmospheric presure, thus causing the foam-forming liquid to cease to be drawn through tube 21.

What I claim as my invention is:

1. A device for mixing and dispensing foam forming liquids, comprising, in combination, a conduit for water. a constricting nozzle in said conduit forming a zone of low pressure in said conduit, a siphon member, support means mounting said siphon member upon said conduit, said siphon member communicating at one end with the interior of said conduit at said low pressure zone, the other end of said siphon member communicating with a source of a second liquid which, together with said water, will form foam, 9. single aperture in said first conduit at said low pressure zone communicating with the atmosphere at the dispensing end of said nozzle for admitting air to said low pressure zone in quantity sufii cient to prevent substantial movement of said liquid through said siphon member, and valve means mounted on said support and operatively associated with said aperture for only partially closing said aperture whereby said second liquid may be aspirated through said siphon 4,. member into said conduit and there mixed with air passing through said partially closed valve, and said first liquid to form foam.

2. The device of claim 1 wherein said source of a second liquid consists of a reservoir detachably secured to said support means.

3. The device of claim 1 wherein said conduit includes an annular interior shoulder downstream from said dispensing end of said nozzle and adjacent said aperture.

4. The device of claim 1 wherein said valve means may be manually operated.

References Cited in the file of this patent UNITED STATES PATENTS 560,922 Pearson May 26, 1896 1,036,871 Matheson Aug. 27, 1912 2,571,871 Hayes Oct. 16, 1951 2,737,413 Mitchison Mar. 6, 1956 FOREIGN PATENTS 35,653 France Oct. 1, 1929 (2nd addition) 

1. A DEVICE FOR MIXING AND DISPENSING FOAM FORMING LIQUIDS, COMPISING, IN COMBINATION, A CONDUIT FOR WATER, A CONSTRICTING NOZZLE IN SAID CONDUIT FORMING A ZONE OF LOW PRESSURE IN SAID CONDUIT, A SIPHON MEMBER, SUPPORT MEANS MOUNTING SAID SIPHON MEMBER UPON SAID CONDUIT, SAID SIPHON MEMBER COMMUNICATING AT ONE END WITH THE INTERIOR OF SAID CONDUIT AT SAID LOW PRESSURE ZONE, THE OTHER END OF SAID SIPHON MEMBER COMMUNICATING WITH A SOURCE OF A SECOND LIQUID WHICH, TOGETHER WITH SAID WATER, WILL FORM FOAM, A SINGLE APERTURE IN SAID FIRST CONDUIT AT SAID LOW PRESSURE ZONE COMMUNICATING WITH THE ATMOSPHERE AT THE DISPENSING END OF SAID NOZZLE FOR ADMITTING AIR TO SAID LOW PRESSURE ZONE IN QUANTITY SUFFICIENT TO PREVENT SUBSTANTIAL MOVEMENT OF SAID LIQUID THROUGH SAID SIPHON MEMBER, AND VALVE MEANS MOUNTED ON SAID SUPPORT AND OPERATIVELY ASSOCIATED WITH SAID APERTURE FOR ONLY PARTIALLY CLOSING SAID APETURE WHEREBY SAID SECOND LIQUID MAY BE ASPIRATED THROUGH SAID SIPHON MEMBER INTO SAID CONDUIT AND THERE MIXED WITH AIR PASSING THROUGH SAID PARTIALLY CLOSED VALVE, AND SAID FIRST LIQUID TO FORM FOAM. 